Toothbrush and attachment therefor

ABSTRACT

An electric toothbrush includes a handpiece with a drive shaft and attachment, which has a working head and a coupling member connecting the working head and the handpiece. The coupling member of the attachment contains a plug-on shaft to engage the drive shaft. An attachment coupling part is axially movable in a longitudinal direction to produce an unlocking or locking movement of the plug on shaft in the transverse direction. The connection can be released and re-established by axial push-on and pull-off movements. A transversely movable engagement part of a coupling contour of the plug-on shaft of the attachment and an actuating part provided on the coupling member are movable in the attachment longitudinal direction, such that relative movement of the actuating part and engagement part in the longitudinal direction produces an unlocking or locking movement of the engagement part in a direction transverse to the attachment longitudinal direction.

TECHNICAL FIELD

This invention relates to an electric toothbrush having a handpiece and an attachment mountable thereon.

BACKGROUND

EP 0 500 537 B1 discloses an electric toothbrush on which the attachment brush is connected on the one hand to a front-end shank part of the toothbrush handpiece and on the other hand to a drive shaft projecting therefrom. For this purpose the attachment brush has radially resilient detent hooks which can be locked in place in corresponding detent notches on the handpiece.

DE 103 52 993 A1 discloses in addition an electric toothbrush on which the attachment brush is fixed only directly to the drive shaft which projects at the front end out of the toothbrush handpiece. For this purpose the attachment brush has a coupling member with an inner recess of the blind-hole type into which an on the whole sleeve-shaped mount is inserted. Said mount, into which the drive shaft can be inserted with a snug fit, includes several spring elements which are radially resilient and intended to ensure a zero-play connection between the attachment brush and the drive shaft.

Excess play in attachment couplings and drive mechanisms can adversely affect handpiece and attachment life and performance. For example, the attachment can become separated due to the vibrations of the electric toothbrush drive and the forces applied by brushing. Accordingly, improvements are sought in electric toothbrushes and attachment tools for treating the oral cavity.

SUMMARY

One aspect of the invention features an electric toothbrush with an improved handpiece and an improved attachment including an easy-to-couple and high tolerance connection between the plug-on shaft of the attachment and the drive shaft of the toothbrush handpiece, The connection couples two sections of the drive train with zero play, and yet can be easily released and re-established. The attachment can include different drive shaft configurations in order to be suitable for use with different toothbrush handpieces.

One aspect of the invention features an attachment connected to a toothbrush handpiece with a drive shaft. The attachment features a working head, a coupling member joined to the working head and mountable on the toothbrush handpiece, and a plug-on shaft for driving the working head. The plug-on shaft is disposed in the coupling member and defines a coupling contour for coupling by positive engagement with the drive shaft of the toothbrush handpiece. Additionally, the coupling contour includes an engagement part movable in a direction transverse to the attachment longitudinal direction and configured to lock with the drive shaft. The transversely movable engagement part is movable in response to movement of the coupling member in the attachment longitudinal direction, to produce an unlocking or locking movement of the engagement part in a direction transverse to the attachment longitudinal direction.

In some implementations, the coupling member further features an actuating part including an unlocking section. The unlocking section is arranged and configured such that during an axial movement of the actuating part away from the working head the unlocking section is movable into engagement with the engagement part and capable of moving the engagement part into an unlocked position.

In some cases, the engagement part and the actuating part define a pair of beveled surfaces configured to produce the unlocking and locking movement while the engagement part rides over the actuating part.

In some cases, the engagement part defines a transverse axis and a detent contour on a protruding end of the engagement part. The protruding end is configured to be radially movable by the actuating part.

In some cases, the engagement part includes a detent ring which is radially extensible and compressible, and has a wedge-shaped surface. Additionally, the dentent ring is radially extensible by a wedge-shaped surface on the actuating part when the detent ring rides axially over the actuating part in the attachment longitudinal direction.

In some cases, the actuating part is connected to a sleeve-shaped coupling insert provided in the coupling member. The coupling insert connects the coupling member to the toothbrush handpiece and is axially displaceable relative to the coupling member in the attachment longitudinal direction.

In some cases, the coupling insert is connected to the toothbrush handpiece by one of positive engagement and frictional engagement. Additionally, an axial movement of the coupling insert relative to the coupling member produces unlocking and locking movements of the engagement section in a direction transverse to the attachment longitudinal direction.

In some cases, the coupling insert forms a sleeve having one of a cylindrical mount and a conical mount configure to receive a complementary connecting part of the toothbrush handpiece.

In some cases, the actuating part features a slide which is axially displaceable in the longitudinal direction of the attachment.

In some cases, the conical mount of the coupling insert has a bevel of more than 7° and is configured in a non-self-locking manner.

In some cases, the plug-on shaft of the coupling member forms one of a detent clip and a spring catch configured to slide along the drive shaft while the coupling member is being plugged onto the toothbrush handpiece and rebound elastically to snap into engagement.

In some cases, the one of the detent clip and the spring catch is unseatable from its snapped-in position by a relative axial movement between the actuating member and the coupling insert.

In some implementations, the coupling contour has one of a conical faying surface and a plurality of circumferentially spaced faying surfaces.

In some cases, the conical faying surface defines a bevel of more than 7°.

Another aspect of the invention features an attachment connected to a toothbrush handpiece having a drive shaft. The attachment features a working head, a coupling member joined to the working head and mountable on the toothbrush handpiece, a plug-on shaft disposed in the coupling member and connectable to the working head, and a coupling contour on the plug-on shaft configured to engage the drive shaft of the toothbrush handpiece. The coupling contour includes at least one conical faying surface configured to engage with a complementary faying surface on the drive shaft of the toothbrush handpiece.

In some cases, the conical faying surface includes a bevel of more than 7°.

In some cases, the coupling member features a sleeve-shaped coupling insert configured to axially lock the coupling member onto a neck of the toothbrush handpiece with the conical faying surfaces on the plug-on shaft and the drive shaft in relative engagement.

In some cases, the coupling contour is axially biased away from the working head.

Another aspect of the invention features an attachment to be connected to a toothbrush handpiece having a drive shaft. The attachment features a working head, a coupling member having an actuating part joined to the working head and mountable on the toothbrush handpiece, and a plug-on shaft within the working head and the coupling member. The plug-on shaft features a coupling contour configured to engage a drive shaft provided on the toothbrush handpiece and includes two coupling contours configured to engage different drive shafts of different toothbrush handpieces.

In some implementations, a first one of the two coupling contours has an engagement part movable in a direction transverse to the longitudinal direction of the attachment for locking with the drive shaft. Additionally, a second one of the two coupling contours includes at least one conical faying surface for engagement with a complementary conical faying surface on the drive shaft of the toothbrush handpiece.

In some cases, the engagement part of the first coupling contour and an actuating part disposed on the coupling member are movable in the attachment longitudinal direction. The engagement part is engageable with the actuating part and configured such that relative movement of the actuating part and the engagement part in the attachment longitudinal direction produces an unlocking or locking movement of the engagement part in a direction transverse to the attachment longitudinal direction. Additionally, the second coupling contour has at least one conical beveled surface defining a bevel of more than 7°.

In some implementations, one of the two coupling contours is defined on an adapter attachable to the plug-on shaft.

Another aspect of the invention features a toothbrush handpiece connected to an attachment having a plug-on shaft and a coupling contour. The handpiece features a neck, and a drive shaft insertable into the plug-on shaft of the attachment and defining a conical coupling contour with a bevel of more than 7°.

In some implementations, the coupling contour is configured to be devoid of undercuts and axially effective snap-action connections.

In some implementations, the drive shaft is axially displaceable relative to the neck of the toothbrush handpiece in the toothbrush handpiece longitudinal direction and biasing means are provided for axially biasing the coupling contour of the drive shaft.

In some implementations, the coupling contour of the drive shaft includes a locking contour extending in a direction transverse to the drive shaft longitudinal direction. The locking contour is non-releasably locked to an adapter which is seatable onto the drive shaft and has on its outer surface a coupling contour for coupling with the plug-on shaft of an attachment.

Another aspect of the invention features an attachment to be connected to a toothbrush handpiece having a drive shaft. The attachment includes a working head and a coupling member joined to the working head and mountable on the toothbrush handpiece; and a plug-on shaft for driving the working head disposed in the coupling member and defining a coupling contour for coupling by positive engagement with the drive shaft of the toothbrush handpiece. The coupling contour includes an engagement part movable in a direction transverse to the attachment longitudinal direction and configured to lock with the drive shaft; and wherein the transversely movable engagement part is movable in response to movement of the coupling member in the attachment longitudinal direction, to produce an unlocking or locking movement of the engagement part in a direction transverse to the attachment longitudinal direction.

In a particular implementation, a tubular coupling member is axially movable in the attachment longitudinal direction and to convert axial movement into an unlocking or locking movement of the coupling of the drive train in a direction transverse to the attachment longitudinal direction for the attachment to engage and disengage the handpiece. The coupling member enables a firm and vibration-resistant connection between the attachment and the handpiece. while enabling the connection to be released and re-established by the axial push-on and pull-off movement.

In some implementations, a transversely movable engagement part of a coupling contour of the plug-on shaft of the attachment and/or an actuating part provided on the coupling member of the attachment are movable in the attachment longitudinal direction, with the engagement part being engageable with the actuating part such that a movement of the actuating part and/or of the engagement part in the attachment longitudinal direction produces an unlocking or locking movement of the engagement part in a direction transverse to the attachment longitudinal direction. If the coupling contour of the plug-on shaft of the attachment is locked onto the drive shaft of the handpiece, the attachment or an actuating part connected thereto can be moved axially in the attachment's longitudinal direction relative to the locked coupling contour, whereby the engagement part of the coupling contour is unlocked in a direction transverse to the toothbrush longitudinal direction to enable the plug-on shaft to be pulled with the attachment off the drive shaft of the toothbrush handpiece.

This attaching or connecting mechanism permits even non-self-locking connecting or faying contours, in particular those with a more pronounced taper, to be provided at the interface of the drive train because fixed connection is assured by the locking movement which takes place in a direction transverse to the attachment's longitudinal direction. In particular, the interface of the drive train can thus be rendered insensitive to tolerances.

To achieve simple operation of the attachment and be able to readily pull the attachment off the toothbrush handpiece, another aspect of the invention features the actuating part having an unlocking section arranged and configured such that during an axial movement of the actuating part away from the working head, the unlocking section is engageable with the engagement part of the plug-on shaft and forces the engagement part into an unlocked position. In other words, the actuating part is arranged and configured such that the actuating part automatically unlocks the coupling insert when the attachment is being separated from the toothbrush handpiece.

In a particular implementation, the attachment includes a working head and

a coupling member joined to the working head and mountable on the toothbrush handpiece. A plug-on shaft is disposed in the coupling member and connectable to the working head a defines a coupling contour configured to engage the drive shaft of the toothbrush handpiece, wherein the coupling contour includes at least one conical faying surface configured to engage with a complementary faying surface on the drive shaft of the toothbrush handpiece.

In a particular implementation, the engagement part of the coupling contour of the plug-on shaft and/or the actuating part defines a wedge-shaped surface, which produces an unlocking movement while the engagement part rides over the actuating part. A pair of plane wedge-shaped surfaces may be provided, but it is also possible to use a pair of beveled surfaces arched in a spherical or concave configuration in the manner of a cam or a cam-type control surface on the one hand and an actuating member riding over it on the other hand. When the engagement part rides over the actuating part as a result of the axial relative movement, the axial movement causes an unlocking movement in a direction transverse to the axial direction.

It is also possible, in reversal of the kinematics, to provide for the actuating part to affect not the unlocking but the locking of the coupling contour of the plug-on shaft or the engagement part connected thereto. In this case the engagement part in its initial position may adopt, or be biased into, a non-locking position. When the attachment is plugged onto the toothbrush handpiece, the engagement part of the coupling is forced into its locking position by way of the actuating part.

The coupling contour of the plug-on shaft can thus be configured to be self-locking while the attachment is being seated onto the toothbrush handpiece, is then released by means of the actuating part while the attachment is being removed again.

In a particular implementation, the engagement part forms a spring catch or a detent clip which, while the coupling member is being plugged onto the toothbrush handpiece, slides along the connecting member of the drive shaft of the toothbrush handpiece, rebounds elastically in the process and, upon reaching the fully plugged-on position, snaps into place by positive engagement. When the attachment is to be removed again from the toothbrush handpiece, the spring catch or the detent clip is unseated from its snapped-in position by a relative axial movement between the actuating part and the spring catch or detent clip.

Generally, the engagement part may be configured in a variety of ways. According to a particular implementation, the engagement part defines a detent contour in the form of a detent hook, which is located at the protruding end of an engagement finger advantageously resilient and/or pivotal about a transverse axis and is radially movable by the actuating part. At least one engagement finger may be integrally made of one piece with the body of the coupling section of the plug-on shaft and be isolated from the rest of the body, for example, by longitudinal slits in order to be resilient in relation to the remaining body. The engagement finger may also be part of a separate coupling attachment secured to the plug-on shaft.

In some implementations, an engagement part can also be provided in the form of a rocker which at its one end has a suitable detent contour, generally in the form of a detent hook for locking engagement with the toothbrush handpiece, and at its other end forms an actuating section which is movable into engagement with the actuating part. In this case, too, the engagement part may be integrally made of one piece with the body of the coupling insert, generally by way of a flexible connecting bar in the middle section of the rocker.

Other implementations may comprise a slotted detent ring on the plug-on shaft, where the ring is radially compressible and extensible. Compression can be accomplished particularly by biasing the detent ring, while conversely an extension or widening of the detent ring can be affected, for example, by way of a pair of beveled surfaces on the detent ring and the actuating part.

The actuating part for unlocking or, if applicable, for locking the coupling of the drive train may be configured in a variety of ways. In a particular implementation, the actuating part is configured for automatic operation so that it operates automatically when the attachment is being pulled off or plugged on, unlocking or locking the engagement part of the drive train coupling automatically.

In some implementations, the actuating part may be connected to a coupling insert, generally being integrally made of one piece therewith, where coupling insert is arranged in the tubular coupling member of the attachment and serves to be locked with the neck of the toothbrush handpiece by positive and/or frictional engagement in order to hold the attachment on the toothbrush handpiece. Furthermore, this coupling insert of the attachment is axially displaceable relative to its coupling member in the attachment longitudinal direction and connected to an engagement part which is lockable with the neck of the toothbrush handpiece by positive or frictional engagement, such that the coupling insert experiences an axial movement in the attachment longitudinal direction relative to the tubular coupling member of the attachment when the attachment is pulled off and/or plugged onto the toothbrush handpiece. When the attachment is pulled off or plugged on, this configuration produces automatically also an axial actuating movement of the actuating part for the drive shaft coupling which is converted into the actuating movement of the engagement part of the drive train coupling in a direction transverse to the attachment longitudinal axis.

In this arrangement, the actuating part is configured in the form of a pulling hook which protrudes from the frontal end of the preferably sleeve-shaped coupling insert and extends as far as the drive train coupling for engagement therewith the engagement part of the coupling contour of the plug-on shaft.

In a particular implementation, the attachment is configured with regard to said coupling insert in such a way that the axial movement of the coupling insert relative to the coupling member and/or an actuating part provided thereon produces an unlocking and/or locking movement of the engagement section of the coupling insert in a direction transverse to the attachment longitudinal direction. If the coupling insert or its engagement section is locked onto the toothbrush handpiece, it is first necessary for the attachment or an actuating part connected thereto to be moved axially substantially in the attachment longitudinal direction relative to the locked coupling insert, whereby the coupling insert initially does not move relative to the toothbrush handpiece on account of its being locked thereto. Not until the axial relative movement has released the lock is it possible for the coupling insert to be pulled together with the attachment off the toothbrush handpiece. This two-stage attaching or connecting mechanism permits even non-self-locking connecting or faying contours to be provided at the interface between the toothbrush handpiece and the coupling insert because fixedly securing is assured nevertheless by the locking movement which takes place in a direction transverse to the attachment longitudinal direction.

As an alternative to the fastening of the actuating part of the drive train coupling to such a coupling sleeve, it is also possible generally for the actuating part to be configured as a part separate from the connecting means of the tubular coupling member on the handpiece neck. For example, the actuating part could be in the form of a slide mounted for displacement on the coupling member, said slide preferably including a fingertip control and/or being displaceable, for example, by a user's thumb in the attachment longitudinal direction relative to the tubular coupling member in order to release or lock the drive train coupling.

The coupling contour of the drive train coupling may be generally shaped in a variety of ways. In a particular implementation, the coupling contour of the plug-on shaft defines a conical mount which widens in a direction away from the working head of the attachment, has a bevel of more than 7° and is accordingly no longer configured to be self-locking, while in corresponding manner the stub-shaped connecting member of the drive shaft of the toothbrush handpiece, which conventionally projects at the front end, may be conically shaped in corresponding manner with a bevel of more than 7°. In reversal of the kinematics, so to speak, it is generally also possible to reverse this arrangement and provide on the drive shaft of the handpiece a conical mount, into which the similarly conical plug-on shaft of the attachment can be plugged. Said relatively pronounced taper of the connecting members of the two shafts renders the connection insensitive to tolerances because any difference in diameter can be compensated for by a corresponding axial movement.

Such a conical configuration of the interface faying surfaces of the drive train coupling is advantageous in connection with the previously described locking of the two shaft parts by means of an engagement part movable in a direction transverse to the attachment longitudinal direction, because such a locking prevents an unwanted disengagement of the relatively cooperating coupling contours even in the presence of a non-self-locking configuration. Nevertheless, the pair of conical faying surfaces enables a firm and zero-play shaft connection to be accomplished which accommodates tolerances.

Additionally, said conical configuration of the faying surfaces of the drive train interface may also be used to advantage with a locking of the tubular coupling member of the attachment brush on the neck of the toothbrush handpiece. By locking the tubular coupling member onto the toothbrush handpiece by positive and/or frictional engagement, also the coupling contours of the plug-on shaft and the drive shaft are securely held against each other without an unintentional disengagement being possible. This has the advantage if the coupling contours of the two shaft parts are biased into their coupling position, which can be accomplished, for example, by guiding the drive shaft axially displaceably in the toothbrush handpiece and biasing it toward the attachment brush by means of a suitable spring device. It is also possible for the plug-on shaft in the attachment brush or at least for the end piece carrying the coupling contour to be biased by a suitable spring away from the working head of the attachment brush, i.e., toward the toothbrush handpiece. In a particular implementation, the plug-on shaft may include two shaft parts slidable one into the other and out of each other in the manner of a telescopic shaft.

The coupling contours on the plug-on shaft and/or the drive shaft can be implemented in a way affording particular ease of manufacture by the absence of any undercuts and axially effective snap-action connections on the coupling contour of the plug-on shaft and the complementary coupling contour of the drive shaft. Accordingly, the two shaft parts can be simply plugged one into the other, with the torque transmission being made possible by the conical faying surface which is generally not symmetrical about the axis. In this arrangement, the axial securing of the coupling contours one upon the other is ensured by the previously described locking of the tubular coupling member of the attachment onto the neck of the toothbrush handpiece.

In a particular implementation, the plug-on shaft of the attachment is configured in respect of its coupling section in such a way that it can be coupled with different drive shafts of toothbrush handpieces.

In some cases, the plug-on shaft of the attachment may include two separate, independently effective coupling contours, each for positive-engagement coupling to different drive shafts of different toothbrush handpieces. In this context, separate and independently effective means advantageously that a drive shaft of the toothbrush handpiece to be coupled to the plug-on shaft is moved into force- or torque-transmitting engagement with a respective one of the two coupling contours.

In a particular implementation, a first one of the two coupling contours has an engagement part movable in a direction transverse to the attachment longitudinal direction for locking, by positive and/or frictional engagement, with the drive shaft of the toothbrush handpiece, while a second one of the two coupling contours includes a conical faying surface for engagement with an equally conical faying surface on the drive shaft of the toothbrush handpiece, which is devoid of undercuts and devoid of axially effective snap-action connections. In a particular implementation, the first one of the two coupling contours may include a transversely movable engagement part, for example, a detent finger, a split detent ring or a pivotal part which is actuatable by way of the axially movable actuating part particularly in the form of a pulling hook secured to the aforedescribed coupling sleeve. The second one of the two coupling contours may be non-self-locking in the manner previously described and it may have a taper with a bevel of more than 7°.

Another aspect of the invention an electric toothbrush attachment including a working head and a coupling member joined to the working head. The attachment is mountable on the toothbrush handpiece, with a plug-on shaft for driving the working head disposed in the coupling member and having a coupling contour for coupling by positive engagement with a drive shaft of the toothbrush handpiece. In some cases, the toothbrush handpiece includes a drive shaft insertable into the plug-on shaft of the attachment with a close fit. In various cases, the attachment can be an attachment brush for dental cleansing, interproximal cleaning devices, gum massage heads or other oral care instrument.

In a particular implementation, the handpiece and attachment comprises complementary connection tapers to permit more lenient tolerances. The drive shaft of the handpiece and the plug-on shaft of the attachment also comprise complementary tapered connection surfaces to enable a connection which allows more lenient tolerances.

DESCRIPTION OF DRAWINGS

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

FIG. 1 is a fragmentary view, in longitudinal section, of one implementation of an electric toothbrush showing the front-end connecting member of the toothbrush handpiece and the attachment brush seated thereon, with the coupling insert, which is seated in the tubular coupling member of the attachment brush, being shown in its locked position.

FIG. 2 is a longitudinal sectional view of the toothbrush of FIG. 1, which is turned through 90° compared to the illustration in FIG. 1.

FIG. 3 is a sectional view of the toothbrush of FIGS. 1 and 2 in the region of the catch mechanism between the coupling insert in the attachment brush and the neck of the toothbrush handpiece.

FIG. 4 is a simplified and enlarged fragmentary view, in longitudinal section, of the electric toothbrush of FIGS. 1 to 3, showing the connection of the plug-on shaft of the attachment brush with the drive shaft of the handpiece of the toothbrush in more detail.

FIG. 5 is a fragmentary view, in section, of the drive train coupling in the coupling member of an attachment brush according to another implementation in which the coupling has a pivotally mounted locking arm with a cam-type actuating part.

FIG. 6 is a fragmentary view, in section, of the drive train coupling in the coupling member of an attachment brush according to another implementation in which the coupling has a pivotally mounted locking arm which is mounted for pivotal movement on a spring part on a side opposite the pulling hook of the actuating part.

FIG. 7 is a fragmentary view, in section, of the drive train coupling in the coupling member of an attachment brush according to another implementation in which the coupling has a pivotally mounted locking arm, with the pulling hook of the actuating part being arranged to act on a side opposite the detent projection of the locking arm.

FIG. 8 is a fragmentary view, in section, of the drive train coupling in the coupling member of an attachment brush according to another implementation in which the coupling includes a split extensible detent ring.

FIG. 9 is a fragmentary view, in longitudinal section, of another implementation in which solely the coupling insert in the coupling member of the attachment brush is locked with the toothbrush handpiece, while the drive train coupling is comprised of conical faying surfaces of the non-self-locking type without axial locking.

FIG. 10 is a fragmentary view, in longitudinal section, of the toothbrush of FIG. 9 in a plane turned through 90° compared to FIG. 9.

FIG. 11 is a sectional view of the connection between the attachment brush and the handpiece of the toothbrush of FIGS. 9 and 10 in the region of the detent hooks of the coupling insert.

DETAILED DESCRIPTION

The toothbrush 1 shown in FIGS. 1 to 3 comprises a handpiece 4 and an attachment in the form of an attachment brush 33. The handpiece 4 comprises in a manner known in the art a housing in which a drive motor and a power supply device, for example in the form of a rechargeable battery, are accommodated and on which an actuating switch for switching the drive on and off is provided. On the frontal end of the handpiece 4 shown in FIG. 1, the housing of the handpiece 4 forms a forward-protruding stub-shaped connecting member 34 which in the implementation shown is conically shaped and tapers towards its free end, with the conical contour of the connecting member 34 having a bevel 35 of more than 7°. Extending from the frontal end of the connecting member 34 is a drive shaft 31 which is adapted to be driven in an oscillatory rotational motion.

The attachment brush 33 comprises a working head 2 with a set of bristles, not shown in greater detail, which in one implementation shown is adapted to be driven in an oscillatory rotational motion about a bristle zone axis pointing approximately in the bristle longitudinal direction. The working head 2 is carried by a whole tubular coupling member 3, which can be plugged onto the neck or the connecting member 34 of the toothbrush handpiece 4. In the interior of the tubular coupling member 3 of the attachment brush 33 comprises a plug-on shaft 29 adapted to be coupled to the drive shaft 31 of the handpiece in a manner preventing relative rotation.

To fasten the attachment brush 33 to the handpiece 4 the tubular coupling member 3 includes a coupling insert 5 in the form of a coupling sleeve, which is accommodated in the tubular coupling member 3 for axial displacement in the direction of the attachment longitudinal direction 38. The inner wall of the coupling member 3 includes an insert mount 16 in which the coupling insert 5 is seated with a snug fit in its locked condition. The insert mount 16 may be configured in a variety of ways. For example, it may be of an on the whole cylindrical or on the whole tapered or conical configuration, or also it may include a cylindrical section as well as a conical section. The insert mount 16 is on the whole slightly conical, with a cylindrical section being provided on its region 40 intended for the inner end of the coupling insert 5.

In a particular implementation, a spring holds the coupling insert 5 axially in the coupling member 3 or biases it into a predetermined initial position. The spring may be provided on the side of the coupling insert 5 close to the working head 2 and be connected to the coupling insert 5 on the one hand and be fixed to the coupling member 3 on the other hand.

The sleeve-shaped coupling insert 5 forms with its inner circumferential surface a mount 13 which is shaped to conform to the outer circumferential contour of the connecting member 34 of the toothbrush handpiece 4 so that the handpiece can be inserted into the mount 13 with a snug fit. The mount 13 is of an on the whole conical configuration, with the bevel of the respective taper adapted to the connecting member 34 and being greater than 7°. The coupling insert 5 has two mutually opposing engagement sections 6 in the form of resilient coupling or spring fingers 12 which are integrally made of one piece with the remaining body of the coupling insert 5 and are separated from the insert by U-shaped slits so that engagement fingers 12 can spring open and shut radially in a direction transverse to the attachment longitudinal direction 38. The engagement fingers 12 extend with their longitudinal axis substantially parallel to the attachment longitudinal direction 38.

As FIG. 1 shows, the engagement fingers 12 carry on their free ends radially inwardly protruding detent hooks 11 adapted to snap into conformably shaped detent notches 41 in the outer circumferential surface of the connecting member 34 of the toothbrush handpiece 4. Other suitable detent contours may be provided, for example, a geometrical reversal of the illustrated implementation comprising detent projections on the connecting member 34 and detent notches on the engagement fingers 12.

As FIG. 3 shows, the connecting member 34 and the mount 13 defined by the coupling insert 5 are not circular in cross section but are both flattened. The connecting member 34 has two mutually opposing flattened surfaces where the detent notches 41 are provided. The engagement fingers 12 have their inner sides complementary to the two flattened surfaces and the detent notches 41 provided therein.

To be able to release the lock shown in FIG. 1 between the coupling insert 5 and the connecting member 34 of the toothbrush handpiece 4, the coupling member 3 of the attachment brush 33 includes an actuating member 7 in the form of a ring which in the illustrated implementation is seated on the frontal end of the tubular coupling member 3 on the side remote from the working head 2. The ring may be colored so that the user is able to identify “his” or “her” attachment brush from the color of the actuating member 7.

In a particular implementation, the actuating member 7 comprises two unlocking sections 8, each in the form of an actuating finger 21 projecting axially in the attachment longitudinal direction into the interior of the coupling member 3. These actuating fingers 21 engage in the mount 13 formed by the coupling insert 5 in the area of the free ends of the engagement fingers 12. Provided on the projecting ends of the actuating fingers 21 are beveled surfaces 10 which serve to cooperate with beveled surfaces on the projecting ends of the engagement fingers 12 of the coupling insert 5. The beveled surfaces 10 are formed such that during the axial riding motion of the engagement fingers 12 over the actuating fingers 21, the engagement fingers 12 are spread radially outwardly, whereby they are lifted out of the detent notches 41 in the connecting member 34 of the toothbrush handpiece 4.

In one implementation, the coupling insert 5 is axially displaceable in the coupling member 3 in order to produce the axial movement. In some cases, the annular actuating member 7 could be axially displaceable in the coupling member 3. The actuating member 7 is however securely seated on the coupling member 3 by a catch mechanism 42 on the inner wall of the coupling member 3.

As shown in FIG. 2, also the coupling interface between the plug-on shaft 29 and the drive shaft 31 is lockable by positive engagement by an engagement part movable in a direction transverse to the attachment longitudinal direction 38. The engagement part 106 is formed by an engagement finger 112 pivotal about a transverse axis 140 and having on its inner circumferential surface a detent projection in the form of a detent hook 111 which protrudes towards the inside of the mount 43 intended for the drive shaft 31. The engagement finger 112 is integrally made of one piece with the body of the plug-on shaft 29. The pivot axle or transverse axle 140 may be formed by weakening the material at selected regions. In the implementation shown, the detent hook 111 is provided in the form of a beveled projection fitting snugly in an approximately V-shaped notch 131 extending in the drive shaft 31 in a transverse direction.

To actuate the engagement finger 112, an actuating part 107 in the form of a pulling hook 132 is provided, which is integrally made of one piece with the previously described sleeve-shaped coupling insert 5 and projects from its frontal surface as far as the area of the drive shaft interface. The pulling hook 132 embraces the end of the engagement finger 112 on the side remote from the transverse axle 140, and a pair of beveled surfaces 109 and 110 is provided at the overlapping ends of the engagement finger 112 and the pulling hook 132 so that, while the engagement finger 112 rides over the pulling hook 132 or vice versa, the axial relative movement between the two parts is converted into a radial actuating movement of the engagement finger 112.

As FIG. 4 shows, the blind-hole-shaped mount 43 in the plug-on shaft 29 includes two independently active coupling contours 130 a and 130 b. The first one 130 a of the two coupling contours is formed by the engagement finger 112 described and an associated plug-in contour of the mount 43 which generally may have a cylindrical section 130 c. In the implementation shown, a complementary drive shaft 31 is plugged in whose engagement section is of an overall cylindrical configuration and whose cross-section is conveniently not circular cylindrical but has a flattened surface on one side in order to ensure a corresponding torque transmission. In this arrangement, the drive shaft 31 is secured to the plug-on shaft 29 by means of the transversely movable engagement finger. The second one 130 b of the two coupling contours is axially spaced from the first coupling contour 130 a and in the embodiment shown is arranged in advance of said first coupling contour 130 a as seen looking from the end of the plug-on shaft 29. In the implementation shown, it is comprised of an overall conical section of the mount 43 which has a plane beveled surface 130 d inclined relative to the longitudinal axis of the plug-on shaft 29, advantageously at a bevel of more than 7°. As shown in FIG. 4, the conical second coupling contour extends as far as into the region of the detent hook 111 so that the second coupling contour may also be utilized in cooperation with the detent hook 111 of the engagement finger 112. As shown in FIGS. 2 and 4, however, the second coupling contour 130 b is not utilized because the drive shaft 31 of the toothbrush handpiece 4 is cylindrically shaped in the described manner.

Consequently, the following mode of operation results:

In a particular application, while the attachment brush 33 is being plugged onto the toothbrush handpiece 4, the connecting member 34 threads into the mount 13 of the coupling insert 5, whereby the detent hooks 11 slides along the outer circumferential surface of the connecting member 34 as the engagement fingers 12 spread open. Upon the fully plugged-on position being reached, the engagement fingers 12 spring radially inwardly causing the detent hooks 11 to engage the detent notches 41 with a snap action. The coupling insert 5 forms a spring catch which upon being plugged onto the toothbrush handpiece 4 locks automatically to the handpiece. In the locked position the connecting member 34 sits in the conical mount 13 with a snug fit. Similarly, the coupling insert 5 is snugly received in the insert mount 16 of the coupling member 3.

To release the positive-engagement lock the user simply needs to pull the attachment brush 33 in the attachment longitudinal direction 38 off the toothbrush handpiece 4. This results first in an axial relative movement between the coupling member 3 and the coupling insert 5 because the latter is held by the detent hooks 11 axially securely on the toothbrush handpiece 4. As the result of such axial relative movement the actuating fingers 21 of the actuating member 7 move under the engagement fingers 12 or the detent hooks 11 so that the engagement fingers 12 are lifted by way of the pair of beveled surfaces 9 and 10 radially out of the detent notches 41. During the axial relative movement between the coupling insert 5 and the coupling member 3, a corresponding deformation of the spring sections 18 and 19 of the spring 17 occurs.

When the engagement fingers 12 with their detent hooks 11 are unlocked from the toothbrush handpiece 4, the coupling insert 5 is pulled together with the coupling member 3 off the handpiece 4. In some implementations, a spring 17 operates to return the coupling insert 5 to its initial position. Due to the conical configuration of the mount 13 and/or a possibly provided follower element, the coupling insert 5 would be pushed back into its locking position when plugged again onto the toothbrush handpiece 4 even in the absence of the spring 17.

At the same time, the axial movement of the coupling insert 5 or of the pulling hook 132 formed thereon causes the lock between the plug-on shaft 29 and the drive shaft 31 to be released. By way of the pair of beveled surfaces 109 and 110, the axial movement of the pulling hook 132 relative to the engagement finger 112 pulls the latter radially outwardly, causing it to be unseated from the notch 131 in the drive shaft 31. The drive shaft 31 can thus be pulled off the plug-on shaft 29.

An alternative implementation of the drive shaft interface and its locking engagement is shown in FIG. 5. The engagement part of the plug-on shaft 29 which affects the locking engagement is provided in the form of a pivotal engagement finger 112 having an inwardly protruding detent hook 111, where the engagement finger 112 forms a pivotal latch or a pawl. In this arrangement, the engagement finger 112 is formed as a part separate from the remaining body of the plug-on shaft 29 and arranged in an axially extending recess 106 in the area of the mount 43, so that the detent hook 111 projects inwardly into the mount 43. The transversely extending pivot axle 140 may be formed by an axle pin, for example.

In the implementation shown in FIG. 5, the engagement finger 112 is actuated by a function arm 135 protruding axially from the coupling insert 5 and forming the actuating part 107. In particular, for actuating the pivotal engagement finger 112 cam-type beveled surfaces 109 and 110 are provided at the front end of the function arm 135 and the engagement finger 112, with the beveled surface 109 on the engagement finger 112 having a lever arm in relation to the finger's pivot axle 140 and in the implementation shown is arranged between said pivot axle 140 and the detent hook 111.

Another variant of the engagement part 106 is shown in FIG. 6, according to which the engagement part 106 is formed by a pivotal pawl 136 which extends transversely across and beyond the mount 43 in the plug-on shaft 29. Similar to the previously described implementations, the detent pawl 136 also has a detent hook 111 for engagement in the notch 131 of the drive shaft 31. In the implementation of FIG. 6, however, the detent pawl 136 is mounted on the plug-on shaft 29 on the opposite side of the detent hook 111 about a pivot axle 140 which equally extends in a transverse direction. A spring device 137 biases the detent pawl 136 into its locking position, and the spring device 137 may be formed by a spring arm integrally formed on the plug-on shaft 29.

To actuate the detent pawl 136, an actuating part 107 in the form of a pulling hook 132 is provided which protrudes from the coupling insert 5 axially as far as the area of the drive shaft interface. Similar to the implementation of FIGS. 1 to 4, actuation of the detent pawl 136 is effected by way of a pair of beveled surfaces 109 and 110.

FIG. 7 shows an implementation of the locking mechanism between the two shafts 29 and 31 similar to FIG. 6. The detent pawl 136 extends transversely across and beyond the mount 43 in the plug-on shaft 29, but in contrast to the implementation of FIG. 6, the transversely extending pivot axle 140 and the detent hook 111 are arranged on the same side of the drive shaft 31. The section 136 a of the detent pawl 136 extending to the opposite side of the mount 43 forms an actuating arm which is actuatable by the pulling hook 132 by way of a pair of beveled surfaces 109 110 similar to the previously described implementation.

Another implementation of the locking mechanism between the plug-on shaft 9 and the drive shaft 31 is shown in FIG. 8. According to this embodiment, the plug-on shaft 29 includes an engagement part 106 in the form of a detent ring 125 which can be radially widened and narrowed, which can be of a longitudinally slotted configuration, for example, to enable its widening. Advantageously, the detent ring 125 may be configured to be elastically biased into its locking, narrowed position. As FIG. 8 shows, the detent ring 125 has on its inner circumferential surface an inwardly protruding detent contour in the form of a detent hook 111 which engages in a notch 131 in the drive shaft 31.

In this arrangement, the detent ring 125 is seated in a circumferential recess on the body of the plug-on shaft 29. In the region of said detent hook 111 the detent ring 125 has on its outer circumferential surface an engagement notch which cooperates with the pulling hook 132 which in turn is integrally formed on the coupling insert 5 in axially protruding manner. Again, a pair of beveled surfaces 109 and 110 may be provided on the detent ring 125 and the pulling hook 132. For the better support, an expansion chamfer may be provided on the recess in the outer circumferential surface of the plug-on shaft 29 and/or on the abutting front edge of the detent ring 125, so that an axial movement of the detent ring 125 relative to the body of the plug-on shaft 29 by means of the pulling hook 132 produces an expanding movement.

The mode of operation of the locking engagement of the drive shaft interface is similar to the previously described embodiments.

FIGS. 9 to 11 show a particular implementation which is generally similar to the implementation of FIGS. 1 to 3. A significant difference lies in the construction of the coupling interface in the drive train. As is shown in FIG. 10, the plug-on shaft 29 of the attachment brush 33 is coupled to the drive shaft 31 of the handpiece by conical faying surfaces, the drive shaft 31 being conically shaped on its end protruding from the housing of the handpiece 4, and a bevel being equally allowed to be greater than 7°. The plug-on shaft 29 has a conformably shaped, frontally open, advantageously blind-hole type mount 43 which comprises a faying surface 130 c which is adapted to the taper of the drive shaft 31 and likewise has a bevel of more than 7°. By firmly plugging on the attachment brush 33, a connection by positive and/or frictional engagement can be established between the plug-on shaft 29 and the drive shaft 31. This connection between the shafts may be free of axially effective snap-action connections or other axial holding means.

To make sure that only one of the two coupling contours 130 a and 130 b of the plug-on shaft 29 is used, for example, to ensure that a user can only use “his” or “her” attachment brush or toothbrush, it is possible for one of the two coupling contours 130 a and 130 b to be covered by non-releasable insertion of an adapter. For example, an adapter could be non-releasably inserted into the mount 43 of the plug-on shaft 29, which adapter closes the first coupling contour 130 a so that the second conical coupling contour 130 b is left for use. Alternatively or in addition, such an adapter could also be provided on the handpiece, in particular by plugging it onto the drive shaft 31 of the toothbrush handpiece 4. For example, a conical adapter could be slipped onto the drive shaft 31 shown in FIG. 4 by way of example and be non-releasably snapped into the notch 131 there, so as to enable a coupling to be effected with the conical second coupling contour 130 b. 

1-26. (canceled)
 27. An attachment mountable to an electric toothbrush handpiece having a drive shaft, the attachment comprising: a working head; a coupling member joined to the working head and configured to mount to the toothbrush handpiece; and a plug-on shaft disposed in the coupling member and defining a coupling contour comprising an engagement part configured to lock with the drive shaft; wherein the engagement part is movable to produce one of a locking movement and an unlocking movement in a direction transverse to a longitudinal attachment axis in response to axial movement of the coupling member relative to the longitudinal attachment axis.
 28. The attachment according to claim 27, wherein the coupling member further comprises an actuating part comprising an unlocking section configured to move the engagement part into an unlocked position during an axial movement of the actuating part away from the working head.
 29. The attachment according to claim 28, wherein the engagement part and the actuating part define cooperative beveled surfaces configured to move the engagement between locked and unlocked positions as the engagement part rides over the actuating part.
 30. The attachment according to claim 28, wherein the engagement part defines a detent contour configured to be radially movable by the actuating part.
 31. The attachment according to the claims 28, wherein the engagement part includes a detent ring which is radially expandable by cooperation with a tapered surface on the actuating part.
 32. The attachment according to claim 28, wherein the actuating part comprises a slide which is axially displaceable relative to the longitudinal axis of the attachment.
 33. The attachment according to claim 28, wherein the actuating part is connected to a sleeve-shaped coupling insert slideably disposed within the coupling member
 34. The attachment according to the claim 33, wherein the coupling insert is configured such that axial movement of the coupling insert relative to the longitudinal attachment axis moves the engagement section between locked and unlocked positions in a direction transverse to the longitudinal attachment axis.
 35. The attachment according to claim 34, wherein the coupling insert is configured as one of a cylindrical mount and a conical mount, and is configured to receive a complementary connecting part of the toothbrush handpiece.
 36. The attachment according to the claim 35, wherein the conical mount of the coupling insert has a bevel of more than 7 degrees and is configured to be non-self-locking.
 37. The attachment according to claim 33, wherein the plug-on shaft of the coupling member comprises one of a detent clip and a spring catch configured to slide along the drive shaft and to rebound elastically to snap into engagement while the coupling member is being mounted onto the toothbrush handpiece.
 38. The attachment according to claim 37, wherein the one of the detent clip and the spring catch is unseatable from an engaged position by a relative axial movement of the actuating member and the coupling insert.
 39. The attachment according to claim 27, wherein the coupling contour comprises one of a conical faying surface and a plurality of circumferentially spaced faying surfaces.
 40. The attachment according to claim 27, wherein the coupling contour comprises one of a conical faying surface defining a bevel of more than 7 degrees.
 41. An attachment to be connected to a toothbrush handpiece having a drive shaft, the attachment comprising: a working head; a coupling member joined to the working head and mountable on the toothbrush handpiece; and a plug-on shaft disposed in the coupling member and defining a coupling contour configured to engage the drive shaft of the toothbrush handpiece, wherein the coupling contour defines at least one conical faying surface configured to engage with a complementary faying surface on the drive shaft of the toothbrush handpiece.
 42. The attachment according to claim 41, wherein the conical faying surface defines a bevel of more than 7 degrees.
 43. The attachment according to claim 41, wherein the coupling member comprises a coupling insert in the form of a sleeve configured to axially lock the coupling member onto a neck of the toothbrush handpiece with the complementary conical faying surfaces of the plug-on shaft and the drive shaft engaged.
 44. The attachment according to claim 41, wherein the coupling contour is axially biased away from the working head.
 45. An attachment to be connected to a toothbrush handpiece having a drive shaft, the attachment comprising: a working head; a coupling member joined to the working head and mountable on the toothbrush handpiece; and a plug-on shaft disposed within the coupling member, and defining two coupling contours, each contour configured to engage a drive shaft of a respective toothbrush handpiece.
 46. The attachment according to claim 45, wherein: a first one of the two coupling contours comprises an engagement part movable in a direction transverse to a longitudinal axis of the attachment to lock with a drive shaft of a first toothbrush handpiece; and a second one of the two coupling contours comprising at least one conical faying surface configured to engage with a complementary conical faying surface on a drive shaft of a second toothbrush handpiece.
 47. The attachment according to claim 46, wherein one of the engagement part of the first coupling contour and an actuating part disposed on the coupling member is axially movable relative to an attachment longitudinal axis, the engagement part configured to cooperate with the actuating part such that relative axial movement of the actuating part and the engagement part produces an unlocking or locking movement of the engagement part in a direction transverse to the attachment longitudinal axis, and wherein the second coupling contour comprises at least one conical beveled surface defining a bevel of more than 7 degrees.
 48. The attachment according to claim 45, further comprising an adapter connected to the plug-on shaft and defining one of the two coupling contours is defined.
 49. An electric toothbrush handpiece configured to be removably connected to an attachment comprising a plug-on shaft and a coupling contour, wherein the handpiece comprises a neck and a drive shaft configured to engage the plug-on shaft of the attachment, the drive shaft defining a conical coupling contour with a bevel of more than 7 degrees.
 50. The toothbrush handpiece according to claim 49, wherein the coupling contour is substantially free of undercuts and axially effective snap-action connections.
 51. The toothbrush handpiece according to claim 49, wherein the drive shaft is axially displaceable relative to the neck of the toothbrush handpiece in the direction of a toothbrush handpiece longitudinal axis
 52. The toothbrush handpiece according to claim 49, wherein the coupling contour of the drive shaft defines a locking contour extending in a direction transverse to the drive shaft longitudinal direction, the locking contour being connected to an adapter seatable onto the drive shaft and defining a coupling contour configured to couple with the attachment plug-on shaft. 